<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <li v-for="(item, index) in goods" class="menu-item" :class="{'current': currentIndex===index}"
          @click="selectMenu(index, $event)">
          <span class="text">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="item in goods" class="food-list food-list-hook">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li v-for="food in item.foods" class="food-item">
              <div class="icon">
                <img width="57" height="57" :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span><span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">¥{{food.price}}</span><span class="old" v-if="food.oldPrice">¥{{food.oldPrice}}</span>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
  </div>
</template>

<script>
  import BScroll from 'better-scroll';
  const ERR_OK = 0;
  export default{
    props: {
      seller: {
        type: Object
      }
    },
    data() {
      return {
        goods: [],
        listHeight: [],
        scrollY: 0,
        selectedFood: []
      };
    },
    computed: {
      currentIndex() {
        for (let i = 0; i < this.listHeight.length; i++) {
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
          if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i;
          }
        }
        return 0;
      }
    },
    created() {
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];
      this.$http.get('/api/goods').then((response) => {
        response = response.body;
        if (response.errno === ERR_OK) {
          this.goods = response.data;
          this.$nextTick(() => {
            this._initScroll();
            this._calculateHeight();
          });
        }
      });
    },
    methods: {
      _initScroll() {
        this.menuScroll = new BScroll(this.$refs.menuWrapper, {
          click: true
        });
        this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
          probeType: 3 // 1为即时触发，3为延迟到事件完毕后触发
        });

        this.foodsScroll.on('scroll', (pos) => {
          this.scrollY = Math.abs(Math.round(pos.y));
        });
      },
      _calculateHeight() {
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        for (let i = 0; i < foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      },
      selectMenu(index, event) {
        // 防止电脑上响应两次
        if (!event._constructed) {
          return;
        }
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
        let el = foodList[index];
        this.foodsScroll.scrollToElement(el, 300);
      }
    }
  };
</script>
<style lang="scss">
  @import '../../common/scss/mixin';
  .goods{
    display: flex;
    position: absolute;
    top: 174px;
    bottom: 46px;
    width: 100%;
    overflow: hidden;

    // 左菜单
    .menu-wrapper{
      flex: 0 0 80px;
      width: 80px;
      background: #f3f5f7;

      .menu-item{
        display: table;
        height: 54px;
        width: 56px;
        padding: 0 12px;
        line-height: 14px;

        &.current{
          position: relative;
          z-index: 10;
          margin-top: -1px;
          background: #fff;
          font-weight: 700;
          .text{
            @include border-none();
          }
        }

        .icon{
          display: inline-block;
          vertical-align: top;
          width: 12px;
          height: 12px;
          margin-right: 2px;
          background-size: 12px 12px;
          background-repeat: no-repeat;
          vertical-align: top;

          &.decrease{
            @include bg-image('images/decrease_3');
          }
          &.discount{
            @include bg-image('images/discount_3');
          }
          &.guarantee{
            @include bg-image('images/guarantee_3');
          }
          &.invoice{
            @include bg-image('images/invoice_3');
          }
          &.special{
            @include bg-image('images/special_3');
          }
        }
        .text{
          display: table-cell;
          width: 56px;
          vertical-align: middle;
          @include border-bottom(rgba(7, 17, 27, 0.1));
          font-size: 12px;
        }
      }
    }
    // 右菜单
    .foods-wrapper{
      flex: 1;

      .title{
        padding-left: 14px;
        line-height: 26px;
        height: 26px;
        border-left: 2px solid #d9dde1;
        background: #f3f5f7;
        font-size: 12px;
        color: rgb(147, 153, 159);
      }
      .food-item{
        display: flex;
        margin: 18px;
        padding-bottom: 18px;
        @include border-bottom(rgba(7, 17, 27, 0.1));
        &:last-child{
          margin-bottom: 0;
        }
        .icon{
          flex: 0 0 57px;
          margin-right: 10px;
        }
        .content{
          flex: 1;
          .name{
            margin: 2px 0 8px 0;
            height: 14px;
            line-height: 14px;
            font-size: 14px;
            color: rgb(7, 17, 27);
          }
          .desc, .extra{
            line-height: 10px;
            font-size: 10px;
            color: rgb(147, 153, 159);
          }
          .desc{
            line-height: 12px;
            margin-bottom: 8px;
          }
          .extra{
            .count{
              margin-right: 12px;
            }
          }
          .price{
            font-weight: 700;
            line-height: 24px;
            .now{
              margin-right: 8px;
              font-size: 14px;
              color: rgb(240, 20, 20);
            }
            .old{
              text-decoration: line-through;
              font-size: 10px;
              color: rgb(147, 153, 159);
            }
          }
        }
      }
    }
  }
</style>
